The Shieldsman (also known as Incognito/Peeping Doom in the SNES/PS version) is an enemy in Chrono Trigger that appears in the Black Omen. It shares similar sprites, albeit with a palette swap, with Sentry. They are small, black spherical beings that hide behind relatively big shields.

When hidden behind their shields, their defense is really high, so it's strategical to wait until they peek out to take a look at the party and attack them then, because their defense lowers significantly. Otherwise the player will be dealing very few damage.